Heretofore as coating resin compositions, many organic solvent dissolution type resin compositions have been used because they can form excellent coat. However, in recent years, from the viewpoints of problems of air pollution and environmental hygiene, safety on fire protection in storage and use, etc., resin compositions dissolved or dispersed in nonpolar organic solvents having relatively high flash points represented by optically inactive aliphatic hydrocarbon solvents have drawn attention.
Among them, non-aqueous dispersion type resin compositions wherein insoluble polymer fine particles are dispersed in organic solvents using polymer dispersion stabilizers have come to be used widely for coating of the inside and outside of buildings, structures, etc. because, in comparison with usual organic solvent dissolution type resin compositions, the above resin compositions have characteristics, for example that they are readily made to have high solid contents and it is possible to reduce the use amount of the organic solvents, and they have thixotropic properties which makes thick coating possible.
As such non-aqueous dispersion type resin compositions, there have been proposed, for example, a non-aqueous dispersion type resin wherein a specific vinyl polymer is used as a dispersion stabilizer (Japanese Laid-open Patent Publication No. 220564/1987), an ordinary temperature dryable non-aqueous dispersion type resin wherein the glass transition temperature of the polymer forming the particles is specified (Japanese Laid-open Patent Publication No. 131632/1991), an ordinary temperature dryable non-aqueous dispersion type resin wherein a specific vinyl graft alkyd resin is used as a dispersion stabilizer (Japanese Laid-open Patent Publication No. 261450/1989), etc.
However, non-aqueous dispersion type resin compositions as mentioned above which so far been proposed have problems, for example that they are inadequate in adhesive properties to various base material surfaces; since pigment dispersibility is inadequate, the storage stability of the paint composition is poor and the viscosity thereof increases with time lapse; lowering of the gloss of the coat is observed; and even if adhesive properties are relatively good, it is difficult to meet, at the same time, coat performances such as alkali resistance and weatherability. Therefore, the resin compositions are not fully satisfactory as coating compositions in practical use.
A main object of this invention is to provide a non-aqueous dispersion type coating resin composition wherein the above disadvantages are overcome, namely which is excellent in pigment dispersibility and adhesive properties to various base material surfaces, can be made to have a high solid content, can be applied thick, and can form coat having good physical properties such as water resistance, alkali resistance and weatherability.